Epson 386SX - Manual (Page 227)

If an error occurs, make a note of the code and message. Then
use the Non-destructive surface analysis (option 3 on the Hard
Disk Format Menu) to check the condition of the hard disk.
If this analysis shows no other problems with the disk, follow
these steps:
1. Back up all the files on your hard disk.
2. Reformat the disk using option 2, Format hard disk, on the
Operation Menu.
3. Install MS-DOS on the hard disk according to the
instructions in the MS-DOS Installation Guide.
4. Restore your files.
Read, Verify Check
This test reads and verifies data from ‘all tracks of the disk,
checking each cylinder and using all read/write heads.
Select option 3 from the menu to start this test. The program
displays the number of each cylinder it finds. For example, with
a hard disk, the first message you see is:
Current cylinder is nnn
The cylinder number counts down to 0. At the end of the test,
you see a table of the results, as follows:
BAD TRACKS ...................
n
READ ERROR TRACKS ............
n
GOOD TRACKS ..................
n n n n
Press ENTER to return to the menu
Performing System Diagnostics C-35